Can't multi select image on Iphone

Question

Hello everybody!
I write one program upload image from iPhone to server use HTTP request.
Current, I use UIImagePickerController to select image and UIImageView to receive and diplay image. Then use UIImageJPEGRepresentation function to get NSData from UIImageView.
I uploaded success image to server use NSURLConnection. But I have some question:
1. Use UIImagePickerController to select image from iPhone, I only select one image. I can't multi select image from iphone. Each upload, I only uploaded 1 image.
Which the way to select multi image to upload them to server in once time.
2. I can't get file name and type (jpg, png,... ) of image, UIImagePickerController only return byte value of image. I can access width and height of image with byte value but can't get name and type of image.
Wich the way to get name and type of image.
3. I found 2 function are UIImageJPEGRepresentation and UIImagePNGRepresentation to covert UIImage to NSData. Current, I use UIImageJPEGRepresentation to convert to NSData:
NSData *imageData = UIImageJPEGRepresentation(img, 1.0);
I think if image is PNG will use UIImageJPEGRepresentation to convert to NSData. But in case image is GIF, BMP,.. which the function used?
Size of imageData more than size of image. So, image upload in server has size more than data of image on Iphone. I don't understannd?
Thank you very much!

Answer 1

1) The image picker does not support multi-select. I think the best you could do is show the user the picker multiple times keeping track of all the images they pick.
2) You can't get the image filename. It would be of no use anyway. When the user takes a picture with the camera, for example, internally the phone stores the image with some internal filename that wouldn't make sense to anyone outside of the phone. Most likely all images are internally stored as JPG but they could be PNG.
3) Images on the phone will never be (I think) GIF or BMP or anything other than PNG and JPG.
There are a lot of conversions going on. The images on the phone are stored as PNG or JPG. When you load them into a UIImage they are converted into an internal bitmap format. If you then use UIImageJPEGRepresentation (or the PNG version) then the internal data is converted to that format. The PNG and JPG formats should be smaller than the internal format due to compression.